This syndrome is characterized by the premature closure of the bones in the skull during development. The skull is made up of various plates of bones which are not completely joined together when an infant is born. As the infant grows older, the sutures fuse together generally after all the head growth has completed. Among the infants with this syndrome, the sutures fuse together before the birth which can normally affect a single or several sutures. In some cases, it is a part of a syndrome and is referred to as ‘syndromic’.
Causes
This syndrome develops as the result of a mutation in the gene identified as FGFR3 that produces the protein involved in the development and maintenance of bone and brain tissue. The genetic mutation results in the overly active protein which can interfere with the normal development of the bone growth allowing the fusing of the bones to occur before they should. This syndrome is inherited in an autosomal dominant pattern meaning a single copy of the defective gene is sufficient to develop this condition.
Symptoms
The symptoms of muenke syndrome are variable with some not exhibiting any signs, others presenting slightly enlarged skull but no fused sutures and a single or both the coronal sutures fuse early causing misshapen skull. The sutures normally expand as the brain continues to grow but the early closure can reduce the room for the growing brain which can increase the pressure inside the skull. The facial abnormalities can include widely spaced eyes, eyes that bulge out, flat cheekbones and the single side of the face that doesn’t match the other. Additional signs can include epilepsy in some cases, webbed or shorter than normal fingers and sensorineural hearing loss. Some of the affected children may also exhibit learning difficulties or developmental delays which can be mild.
Diagnosis
The diagnosis of muenke syndrome is based on the examination of the child’s skull to determine if the shape indicates whether any of the sutures have closed too early. The diagnosis may also be suspected based on the additional features associated with this condition. A CT scan of the child’s head can give more information about the problems and to determine the form of treatment required for the child. The genetic testing can help identify the genetic mutation responsible for the development of the condition.
Treatment
The treatment normally should be initiated immediately after the child is born based on the functional and appearance-related requirements. As this condition can also affect various other parts of the body, a multidisciplinary team approach is required consisting of craniofacial surgeons, neurosurgeons, ENT surgeons, dentists and orthodontists. The surgical procedure involves making an incision through the fused structures in the skull and then reshaping it to give a normal shaped skull. In the case of the sensorineural hearing loss, the hearing aids can be fitted or the cochlear implant may be required. As the bones continue to grow, the affected child may require surgery in the future to make minor corrections to the shape of the skull.
References
http://www.gosh.nhs.uk/medical-information-0/search-medical-conditions/muenke-syndrome
https://ghr.nlm.nih.gov/condition/muenke-syndrome#inheritance
http://www.chop.edu/conditions-diseases/muenke-syndrome
http://www.seattlechildrens.org/medical-conditions/chromosomal-genetic-conditions/muenke-syndrome/
https://rarediseases.info.nih.gov/diseases/7097/muenke-syndrome
